My comptech manual doesn't cover this and I didn't have luck doing a search. Can anyone tell me the correct spark plugs to use for a 1991 with high boost whipple CTSC and headers, street driven in Florida? (Actual boost is about 6.5 psi.
Thanks for any help!
The platinum plug is a little more expensive than the Iridium plug, however, they last longer and will do less damage to the engine if the tip ever breaks.
yes the laser platinum is a good choice p/n 5555 or you could use the iridiums(waste of money) but only the laser iridium #6741(even more of a waste of money)
lots of people like to use the cheap g-power #7092 - or even v-groove ngk's #2756 - and just throw them out often
The platinum plug is a little more expensive than the Iridium plug, however, they last longer and will do less damage to the engine if the tip ever breaks.
I am puzzled.
Over the last year and a half I have been reading that for supercharger application the iridium plug was advised (SOS still has this advise on their website too).
Now all of a sudden it is back to a platinum advise??
What has caused this change in opinion??
Ive never ran a platinum plugs in any of the boosted cars ive tuned due to the many claims people have destroyed the electrodes with forced induction applications.
Iridium plugs are just fine, but at more cost than copper plugs. More care needs to be taken w/ gapping iridium plugs.
Copper plugs are normally what I recommend. They are usually 3-5 dollars a piece, and in the NSX, spark plugs are easy to change. The theory is that iridium plugs last longer, but I have many many cars running on the same copper spark plugs for years at a time. Naturally depending upon how good the car is tuned, not to mention how hard the car is driven, the plugs may or may not last as long.
My recommendations: NGK 3330's for NSX FI cars making up to 700 whp. Gap: Depends on FI Setup, for most of you .028-.030.
I can see why a track driven car would need colder plugs. I am puzzled why a street driven SC car which would very rarely experience boost for more than 5 seconds needs colder plugs. Wouldn't this contribute to plug fouling, especially since I think the SC cars run a little richer?
I am puzzled.
Over the last year and a half I have been reading that for supercharger application the iridium plug was advised (SOS still has this advise on their website too).
Now all of a sudden it is back to a platinum advise??
What has caused this change in opinion??
This might not apply here, but supra guys have been using regular copper plugs, or ngk6097 with a gap of .26-.28. These are the high boost guys too, running a good 20+ at times.
On my BBSC (running five psi) I just used stock, and never had an issue.
The platinum plug is a little more expensive than the Iridium plug, however, they last longer and will do less damage to the engine if the tip ever breaks.
I have been running BKR7E-IX iridium plugs on my low boost NSX for 3 years, no problems. I went with Iridium not for the cost saving, it is just that I heard too many horror stories on Supraforums with platinum plugs. It could be just the internet, so it is most likely false.
Titan Motorsports only recommend Copper or Iridium spark plugs for boosted Supras.
I do agree that the copper NGK 3330 (available at Pepboys or Autozone) or 6097 (special order) are great choice, I used to run 6097 on Supra, but I change them out with every oil change, no joke. It is a 5 minute DIY job. Wish it is this easy changing spark plugs on NSX.
Although different car, the NGK spark plugs work fine on NSX.
Q. How often should I change my plugs?
A. Copper based (standard) plugs 4-6,000miles
Platinum 25,000 miles
Iridium 30,000miles
Q. Why are there different heat ranges? Which one should I use?
A. Part of your spark plug’s responsibilities, in addition to firing a spark, is to remove heat from the combustion chamber. This is accomplished by channelling the heat through the insulator material and metal housing. From there, the heat is transferred to the cylinder head where the engine cooling system can go to work. A spark plug’s heat range is its ability to dissipate heat. The colder the plug, the more heat it can channel out of the combustion chamber. In a performance application, colder heat ranges may be necessary to handle the extreme temperatures brought on by higher compression ratios, forced induction, and high RPM’s. While colder plugs may seem to be the way to go, please remember that the spark plug must achieve its self-cleaning temperature where it can burn off fuel and carbon deposits. Otherwise, the plug could foul out where it is prone to misfiring and poor acceleration. A plug that is too hot can overheat, also causing power loss, detonation, pre-ignition, and possible engine damage. A good, general rule of thumb is to start with the factory recommended heat range. For every 75 to 100 hp you add to your engine, you may go to the next colder step.
Q. What's the difference between the BCPR*ES (3330) and the BKR*E (6097) that get recommended a lot?
A. These 2 plugs are IDENTICAL in operation and completely interchangeable. But, the BKR*E is the recommended fit. One difference is that the BKR*E has an ISO sized connector to the coil pack and the BCPR*ES has a slightly larger one. The other obvious difference is that they BKR uses a V-groove electrode and the BCP uses a flat electrode. I would recommend using BKR*E's first but switch to BCPR*ES's if you have an ignition problems as I believe tired coil packs that have seen many a change will be slightly stretched inside and will benefit from having a larger plug body to fit over.
Plug selection
Note - This selection list does not take Nitrous into account. If you have Nitrous go one grade colder than this table advises at your boost/performance level.
Rule of thumb
Iridiums should always come pregapped correctly - altering the gap will cause damage. If you test the gap and it isn't correct return them to the stockist and check they got in the right version.
Normally Aspirated
NGK - Standard - BKR5ES-11 (2382) - gap is already 1.1mm at the "-11" signifies they should be set to this already.
NGK - V-Power - BKR5EYA-11 (2526) - gap is already 1.1mm at the "-11" signifies they should be set to this already.
NGK - G-Power Platinum - BKR5EGP (7090) - gap to 1.1mm
NGK -Laser Platinum - BKR5EP-11 (3440) - gap is already 1.1mm at the "-11" signifies they should be set to this already.
NGK -OE Laser Iridium - IFR5T11 (4996) - gap is already 1.1mm at the "-11" signifies they should be set to this already.
NGK - Iridium IX - BKR5EIX-11 (5464) - gap is already 1.1mm at the "-11" signifies they should be set to this already.
Denso Platinum - PK16R11 - gap to 1.1 (but always check first)
Stock TT
NGK - BCPR6EP-11 - gap is already 1.1mm at the "-11" signifies they should be set to this already.
NGK - BKR6E (2756) - gap 1.1mm
NGK Iridium - BKR6EIX-11 (3764) - gap is already 1.1mm at the "-11" signifies they should be set to this already.
Denso Platinum - PK20R11 - gap 1.1mm
Denso Iridium - IK20 - leave gap alone
TT @ upto 1bar
NGK - BCPR7ES (3330) - gap 0.9mm
NGK - BKR7E (6097) - gap 0.9mm
NGK - Iridium - BKR6EIX or BKR7EIX - leave gap alone
Denso Platinum - PK20R11 - gap 0.8mm
Denso Iridium - IK22 - leave gap alone
TT/hybrids @ upto 1.3bar
NGK - BCPR7ES (3330) - gap 0.7mm
NGK - BKR7E (6097) - gap 0.7mm
NGK - BKR8E - gap to 0.7mm
NGK - BCPR8ES (3330) - gap 0.7mm
NGK Iridium - BKR7EIX - leave gap alone
NGK Iridium - BKR8EIX - leave gap alone
Denso Platinum - PK20R8 - gap 0.7mm
Denso Iridium - IK22 - leave gap alone
Denso Iridium - IK24 - leave gap alone
Single Turbo/Big Twins @ upto 1.3bar
NGK - BCPR7ES (3330) - gap 0.7mm
NGK - BKR7E (6097) - gap 0.7mm
NGK - BKR8E - gap to 0.7mm
NGK Iridium - BKR7EIX/BKR8EIX - leave gap alone
Denso Iridium - IK24 - leave gap alone
Single Turbo/Big Twins @ upto 1.8bar
NGK - BCPR8ES - gap 0.6-0.7mm
NGK - BKR8E - gap 0.6-0.7mm
NGK Iridium - BKR8EIX - leave gap alone
Denso Iridium - IK27 - leave gap alone
Single Turbo/Big Twins @ 2+bar
NGK - BCPR8ES - gap 0.6mm ??? UNTESTED
NGK - BKR8E - gap 0.6mm ??? UNTESTED
NGK Iridium - BKR8EIX or BKR9EIX? - leave gap alone ??? UNTESTED
Denso Iridium - IK27 to IK31 - leave gap alone ??? UNTESTED
Is this information still valid? The post by nsxsupra seems to show gap measurements for supras (don't see any mention for CTSC). Another poster said 0.28 ~ 0.30 for CTSC. Is this good for all plugs? There seems to be some conflicting information on here with one poster saying be sure to gap iridium plugs correctly and another saying they come pre-gapped at 1.1mm and should not be changed.
My 7.3lb boost CTSC started running rough under heavy throttle. To cut a long story short, swapped out the slightly fouled two year old NGK BCPR7ES plugs for a set of new NGK VPower BKR7E, and saw these results....ambient temp around 78 degrees
The first run was when I got there, and I think the second was before we regapped them. The last two were back to back runs.
Clearly one plug has had water in the well - coil looked OK inside the sleeve but I still see a slight miss around 6k under WOT so will swap out the coil as well. Not sure to what extent the problem was caused by the one corroded plug by itself.
So the question now is, am I pushing too close to the limits.....?
My 7.3lb boost CTSC started running rough under heavy throttle. To cut a long story short, swapped out the slightly fouled two year old NGK BCPR7ES plugs for a set of new NGK VPower BKR7E, and saw these results....ambient temp around 78 degrees
The first run was when I got there, and I think the second was before we regapped them. The last two were back to back runs.
Clearly one plug has had water in the well - coil looked OK inside the sleeve but I still see a slight miss around 6k under WOT so will swap out the coil as well. Not sure to what extent the problem was caused by the one corroded plug by itself.
So the question now is, am I pushing too close to the limits.....?
The plug looks only rusted above the thread which means it's not happening inside the motor. (yay...)
The trim that fits over the coil packs that sits on the cam cover has a gasket which is known to go, it is also possible it's mounted the wrong way around as from memory i believe they only have a gasket on one side which should be on the top side of the engine. I guess it could also be possible you have a screw missing so it's not sealing, there should be 4 bolts, one per corner then you also have which could easily be missed is the two nuts that go in the middle of the cover. The water leaks in from there, I think there is also a seal half way down the chamber the plugs screws in but if it's leaking water from there I can't imagine that being good at all.
I would say it's very likely to be the leaky top cover. If i had to take a guess, i would say that plug was from the back head? you seem to get more water coming in and sitting on that one.
Coil packs are electrical, any water getting in can not be good. I would get that fixed.
very cheap fix replacing the seal. :redface:
Make sure when you remove the old seal you clean the surface on the plastic cover so it seals once bolted in to place.
- - - Updated - - -
I've just bought 2 sets of BKR8EIX Heat range 8 Iridium's.
Are you guys saying i don't need to gap these?
I gapped my last set to what i was advised to gap them to if they were coppers.
What are the advantages of gapping a plug? is it just to stop spark blow out? are there any disadvantages accept potentially damaging the tip?
I replace the plugs twice a year normally. Just got in the habbit of doing it.
The plug looks only rusted above the thread which means it's not happening inside the motor. (yay...)
The trim that fits over the coil packs that sits on the cam cover has a gasket which is known to go, it is also possible it's mounted the wrong way around as from memory i believe they only have a gasket on one side which should be on the top side of the engine. I guess it could also be possible you have a screw missing so it's not sealing, there should be 4 bolts, one per corner then you also have which could easily be missed is the two nuts that go in the middle of the cover. The water leaks in from there, I think there is also a seal half way down the chamber the plugs screws in but if it's leaking water from there I can't imagine that being good at all.
I would say it's very likely to be the leaky top cover. If i had to take a guess, i would say that plug was from the back head? you seem to get more water coming in and sitting on that one.
Coil packs are electrical, any water getting in can not be good. I would get that fixed.
very cheap fix replacing the seal. :redface:
Make sure when you remove the old seal you clean the surface on the plastic cover so it seals once bolted in to place.
Thx, yes we replaced the plugs and that coil. Found that the cover was not seated right due to stripped bolts, which I will fix when we do TB/WP in a few weeks.
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